The present invention relates generally to an integrated circuit (IC) design, and more particularly to a system for smoothing the output voltage level of a charge pump circuit to optimize power management and improve data integrity.
Charge pump circuits are generally used for generating higher voltages from low voltage inputs. It is typically used for providing a steady level of output voltage. The provision of these higher voltages is critical in many low voltage applications such as notebook PCs, mobile phone cables and mobile phone display panels. It is commonly used to improve power efficiency in battery powered applications.
A conventional charge pump circuit is typically comprised of a charge pump device, a level detection device, and a ring oscillator. They are placed in a feedback loop configuration. A level detection device is designed to monitor the output of the charge pump circuit to determine when the ring oscillator and the charge pump device need work together to generate an internal voltage output.
However, with only one charge pump device and one fixed frequency ring oscillator, the conventional charge pump circuit is designed to provide the same supply current irrespective of the load. For such a charge pump circuit with a constant drivability, the circuit has to supply the largest output current to sustain the current demand for the worst case. This can be a problem during standby conditions or low loading cases since the current may overshoot, thereby causing not only significant voltage level bouncing but also corruption to data integrity.
Therefore, it is desirable to design a new charge pump that can reduce the unnecessary power consumption caused by standby or low loading conditions while improving the data integrity by suppressing the bouncing of voltage level generated from the charge pump.